Lists all SGI tag identifiers.

Values:

IGMDTAG_ID_SGI_FORMAT	SGI metadata format identifier.
IGMDTAG_ID_SGI_MAGIC	IRIS image file magic number. R/O.
IGMDTAG_ID_SGI_STORAGE	Storage format. R/O.
IGMDTAG_ID_SGI_BPC	Number of bytes per pixel channel. R/O.
IGMDTAG_ID_SGI_DIMENSION	Number of dimensions. R/O.
IGMDTAG_ID_SGI_X_SIZE	X size in pixels. R/O.
IGMDTAG_ID_SGI_Y_SIZE	Y size in pixels. R/O.
IGMDTAG_ID_SGI_Z_SIZE	Number of channels. R/O.
IGMDTAG_ID_SGI_PIX_MIN	Minimum pixel value. R/W.
IGMDTAG_ID_SGI_PIX_MAX	Maximum pixel value. R/W.
IGMDTAG_ID_SGI_DUMMY1	Dummy 1 value. R/W.
IGMDTAG_ID_SGI_IMAGE_NAME	Image name. R/W.
IGMDTAG_ID_SGI_COLOR_MAP	Color map. R/O.
IGMDTAG_ID_SGI_DUMMY2	Dummy 2 value. R/W.